Muffling and oil-cooling device



Oct. 15, 1957 w. s. FLETCHER 2,309,313

MUFFLING AND OILCOOLING DEVICE Filed Jan. 24, 1955 W 'NDELL. 5'. Mercy/E12.

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United States Patent MUFFLING AND OIL-COOLING DEVICE Wendell S. Fletcher, South Pasadena, Calif.

Application January 24, 1955, Serial No. 483,535

6 Claims. (Cl. 257-16) This type of cooling action by means of a jet of exhaust gas has been known for many years and a great many efforts have been made to manufacture automotive and other vehicles employing this type of cooling. These efforts have met with various degrees of success. A major problem has been encountered with jet cooling in reducing the noise level of the engine to a satisfactory extent.

it is a broad object of the present invention to provide mufiling means which are comparatively small, cheaply constructed, and very efficient, these muflling means being designed to be employed with engines cooled as indicated. Further objects of the present invention as well as certain advantages of it will be more fully apparent in the remainder of this specification, including the appended claims and the accompanying drawing.

The instant invention may be briefly summarized as required by the Patent Ofiice Rules as being concerned with a mutiling device for an engine from which there project pipes conveying a mixture of exhaust gases and cooling air, these pipes being arranged in pairs, one of said pipes leading into a closed end of a cylinder having a closed end and an open end, and the other of these pipes leading into the central portion of said cylinder, this cylinder being provided with an interior construction which is designed to absorb sound. The invention is best more fully explained with reference to the accompanying drawing forming a part of this description. In the drawing:

Fig. 1 is a diagrammatic end view showing an internal combustion engine muifled in accordance with this disclosure;

Fig. 2 is a side view taken in the direction of the arrow 2 in Fig. 1;

Fig. 3 is a partial cross-sectional view taken at line 33 of Fig. 1;

Fig. 4 is a partial cross-sectional view corresponding to Fig. 3 of a modified mufiiing construction of the instant invention; and

Fig. 5 is a top view taken in the direction of the arrow 5 in Fig. 1, illustrating a slightly modified muflling device of the category shown in Figs. 1, 2 and 3 of the drawing.

In Fig. 1 there is shown an internal combustion engine which is designed to be cooled by means of an air stream drawn past various heated portions of this engine by means of a jet of exhaust gas. Cooling means of this category are well known to the art, and hence the accompanying drawing does not illustrate the precise construction herein involved. However, reference may be made to the copending Thorp et al. application Serial No. 381,880, filed September 23, 1953, now Patent No. 2,737,- 164, for details of an operative device for drawing cooling air streams past various portions of an internal combustion engine.

A mixture of exhaust gases for cooling air created as a result of this cooling operation is passed from the engine 10 through pipes 12 and 14 to mufiling cylinders 16. These mutfling cylinders 16 include open ends l8 Patented Oct. 15, 1957 and closed ends 20. Further, these mufiiing cylinders 16 are provided with interior perforated metal shells 22 which are spaced from their imperforate outer walls 24 by means of sound-absorbing fiber-glass packing 26. Those skilled in the art will realize that this construction of the mufliing cylinders 16 makes these cylinders particularly adaptable for use in absorbing sound.

The mixture of exhaust and cooling gas conveyed through the pipes 12 and 14 to the muffiing cylinders 16 in effect carries with it a large amount of sound because of the operation of the internal combustion engine 10 emitting periodical blasts of exhaust gases. The pipes 14 are connected into the rnufiling cylinders 16 centrally of the closed ends 20 by means of the pipes 14 leading into these ends so as to lie flush therein disposed centrally within the ends 20. The pipes 12 are connected to the mutliing cylinders 16 so as to pass through the sides of these mufiiing cylinders into the center portions of them. Here, the pipes 12 are curved slightly so as to be provided with open ends 30 so that a line drawn perpendicularly to either of the open ends 30 is at an acute angle with respect to the axis of the mufiiing cylinder 16 within which this particular end is disposed. Further, the open ends 31 of the pipes 12 are preferably placed off center within the muflling cylinders 16.

The precise mechanism by which the construction described above is operative in muflling sound is not cornpletely understood. The muflling devices of the present invention are distinguished by virtue of the fact that they have very little back pressure which tends to impede the operation of the cooling means employed with the engine 10, yet they are exceedingly effective for the purpose intended. Probably the configuration of the mufiiing devices shown is such as to give rise to an interference between sound conveyed from the engine 10 through the pipes 12 and 14 within the cylinders 16, such interference causing sound waves to be reflected within the muffling cylinders 16 until such time as they are absorbed to a substantial extent.

The efficiency of the mufiiing devices of the present invention is quite surprising in view of their comparative small size and extreme effectiveness. An automotive vehicie utilizing a four-cylinder, horizontally opposed engine which is cooled in accordance with the disclosure of the aforesaid Thorp et al. application Serial No. 381,880 has been satisfactorily mufficd utilizing the precise construction shown in Figs. 1, 2 and 3 of the drawing. With the rnufliing device employed with this vehicle, the muiiling cylinders were approximately 16" long, and approximately 6" in diameter. The open ends 28 of the pipes 14 and the open ends 30 of the pipes 12 were approximately 2 /2 in diameter with this construction.

It is possible to modify the construction shown in Fig. 3 of the drawing slightly as illustrated in Fig. 4 of the drawing. Here, the closed end 20 of a muflling cylinder 16 is replaced by means of an elongated open end 32 which is occupied by an oil cooler 34 which is designed to receive oil from an internal combustion engine through a pipe 36, and to convey cooled oil back to the same engine through an outlet pipe 38. The oil cooler includes end distributing and collecting manifolds 40 of substantially conventional design, and is provided with an interior lattice-work arrangement 42 of the type conventionally used in automobile radiators and like constructions for cooling liquid by means of gas flowing past this lattice-work. With the construction shown in Fig. 4 of the drawing. the ends 30 and 28 of the pipes 12 and 14 exercise a pumping action which tends to pull air during the operation of the muflling cylinder 16 through this lattice-Work 42, and thence out through the open end 18. The lattice-work 42 in this construction exercises a substantial rnufiling action tending to supplement the action of the muff-ling material disposed within the mutfiing cylinder 16. As is quite apparent from Fig. 4, the end 28 of pipe 14 is located centrally within the mutiling cylinder 16 so that the axis of this open end 28 is coincident with the axis of the mufiling cylinder 16.

In Fig. of the drawing, a modified construction of the invention is shown which is very closely related to the construction illustrated in Figs. 1, 2 and 3 of the drawing, but ditters from the construction shown in these initial three figures primarily in that the mufiling cylinders 16 are curved slightly. This type of construction is acceptable with the invention provided that the degree of curvature of the muffiing cylinders 16 is comparatively small so that no additional back pressure is exerted by virtue of this curvature which would tend to afiect the cooling means employed with the internal combustion engine 10.

Those skilled in the art will realize that a wide variety of modifications may be made within the scope of the present invention without departing from the essential teachings of it. All such modifications are to be considered as part of the inventive concept insofar as they are defined by the appended claims.

I claim as my invention:

1. An apparatus for rnufiling internal combustion engines which are cooled by means of streams of air being drawn past portions of such engines by jets of exhaust gases emitted from these engines, which comprises: a muflling cylinder, said rnuffiing cylinder being provided with a perforated inner Wall; an imperforate outer wall and sound-absorbing packing spaced between said inner and said outer walls; a pipe connected to said engine for conveying a mixture of exhaust gases and cooling gas from said engine, said pipe leading into said mufliing cylinder so that an open end of said pipe is disposed axially in said mufiiing cylinder, said open end of said pipe being of smaller diameter than said inner Wall; and a second pipe for conveying a mixture of exhaust gases and cooling gas from said engine projecting through said inner and outer walls into said mufiling cylinder through the side thereof into the center portion of said mufiling cylinder, said second pipe having an open end within said muilling cylinder.

2. A construction as defined in claim I, wherein said open end of said second pipe is inclined with respect to the axis of said mufiling cylinder.

3. A mutiling device as defined in claim 1 wherein said cylinder is open at both ends whereby air is pulled through said mufiiing cylinder from one end to the other by the action of gases emitted from said pipes and wherein an oil cooler is disposed within said mufiling cylinder intermediate the ends of said pipes and said one end of said cylinder.

4. A mufliing device as defined in claim 1, wherein said cylinder is curved.

5. Apparatus for mutfiing internal combustion engines comprising a muflling cylinder having an imperforate end wall and an imperforate outer wall, a perforated inner wall, sound absorbing packing between said inner and outer walls, a pipe for conveying exhaust gases from said engine to said muffiing cylinder entering said cylinder coaxially thereof through said end wall, the diameter of said pipe being less than the diameter of said inner wall whereby the passage for said gases is abruptly enlarged at the end of said pipe, and a second pipe for transmitting exhaust gases to said mufiling cylinder projecting through said inner and outer walls substantially midway of the ends of said cylinder, said second pipe having an open end facing away from said end wall and inclined with respect to the axis of said mufliing cylinder.

6. In apparatus for muffling internal combustion engines comprising, an open ended muifiing cylinder, at least one pipe for conveying exhaust gases from said engine to said cylinder, said pipe projecting through the side of said cylinder and having an open end facing one end of said cylinder whereby a flow of air is induced through said muffling cylinder from the other end thereof towards said one end by the action of exhaust gases emitted from said pipe, and an oil cooler disposed within said mufiiing cylinder between said pipe and said other end of said mufiiing cylinder to be cooled by the flow of air through said muflling cylinder.

References Cited in the tile of this patent UNITED STATES PATENTS 1,431,120 Krafve Oct. 3, 1922 2,046,193 Spicer June 30, 1936 2,144,506 Potter Jan. 17, 1939 2,537,203 Bourne et a]. Jan. 9, 1951 FOREIGN PATENTS 522,861 Great Britain June 28, 1940 

